trivial: cgroups: documentation typo and spelling corrections

Minor typo and spelling corrections fixed whilst reading
to learn about cgroups capabilities.

Signed-off-by: Chris Samuel <chris@csamuel.org>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/cgroups/devices.txt b/Documentation/cgroups/devices.txt
index 7cc6e6a..57ca4c8 100644
--- a/Documentation/cgroups/devices.txt
+++ b/Documentation/cgroups/devices.txt
@@ -42,7 +42,7 @@
 movement as people get some experience with this.  We may just want
 to require CAP_SYS_ADMIN, which at least is a separate bit from
 CAP_MKNOD.  We may want to just refuse moving to a cgroup which
-isn't a descendent of the current one.  Or we may want to use
+isn't a descendant of the current one.  Or we may want to use
 CAP_MAC_ADMIN, since we really are trying to lock down root.
 
 CAP_SYS_ADMIN is needed to modify the whitelist or move another